Hello, I think it’s the same issue than this one : https://forums.unrealengine.com/t/unable-to-launch-a-session-we-hit-an-error-while-cooking-this-content-errors-com-epicgames-content-service-cook-failure
Really interesting, you found the issue was linked to world streaming, it’s also enabled in our project. And like you, we need it absolutly.